1-2-2 



Germination of Indigenous Seeds. 



[May, 



considerable injury due to Thrips (Thrips cerealium)* while 

 tall fescue was also attacked by a grub not yet identified. These 

 attacks were responsible for a failure of much of the heavy 

 seed to germinate and also gave rise to much light seed and 

 impurity, t 



Another factor influencing the poor quality of collected seed 

 is probably connected with the variable nature of any particular 

 habitat from which seed is collected. Seed collected in bulk 

 from hedges will be taken from numerous sub-habitats — from 

 the top, bottom and different sides of a hedge, while from 

 thickets there will be every degree of exposure to light and 

 shade. Thus it is impossible to collect any considerable 

 quantity of seed all under reasonably identical conditions of 

 growth and harvest, and still less under the best conditions. 

 This may be achieved with fair success in the case of plants 

 growing in large masses together. Thus perennial rye grass 

 growing in relatively large practically pure association near the 

 Harbour at Aberystwyth and harvested when nicely ripe gave 

 a germination of 88 per cent., while a lot of lb. of cocksfoot 

 collected from the top of a long hedge germinated 54 per cent., 

 compared with a lot of 7 lb. collected from a thicket germinating 

 44 per cent, and with a 8 lb. lot from another thicket germinat- 

 ing only 12 per cent. Individual panicles and small bunches 

 of panicles were, however, selected from numerous habitats, the 

 seed of which germinated over 80 per cent. Crested dogstail 

 collected off old permanent pastures with a southern aspect 

 has given attractive bright samples germinating over 90 

 per cent. 



The " once grown " seed at Aberystwyth under uniform 

 garden and field conditions has on the average germinated 

 better, and in practically all cases has given considerably more 

 heavy seed than the collected, and this despite the very un- 

 favourable harvest conditions of 1920. 



It is of interest to note in this connection that " once 

 grown " cocksfoot was less severely attacked by the larvae of 

 < rhiphipterijx fischeriella than the collected. 



A comparison of the grain weight of heavy indigenous seed 

 with that of heavy commercial seed, as with the legumes, shows 

 the advantage as to weight to be considerably in favour of the 

 commercial. The only exception is meadow foxtail, in the case 

 of which, however, only very inferior commercial samples 



* See " Preliminary Investigations with Herbage Plants," loc. sit. 

 f Single husks and chaff. 



